Flavor additives have long been used to flavor a wide variety of consumer products, particularly tobacco products, foodstuffs, and gums. Flavor additives in such products may be used to mask or attenuate undesirable flavors or odorants, and to enhance existing flavors or odors, or to provide additional flavors or odors not initially present in the consumer product.
A principal strategy currently employed to impart flavors or odors to consumer products is the admixing of the flavorant chemicals within a matrix that slows or prevents their release until the product is pyrolyzed, heated, masticated or wetted. Alternatively, the flavoring chemical may be covalently bound to an auxilliary component to form a higher weight molecule of low volatility. The flavorant is then released upon pyrolysis, heating or solvolysis of the tobacco or food product.
For example, European patent 186,502 describes the use of a plastic capsule that releases flavorants when mechanically crushed.
U.S. Pat. No. 4,001,438 describes flavor compositions for use in orally utilizable compositions which may be either chewing gum compositions, chewable medicinal tablets, chewing tobacco or toothpaste. The flavor is controllably released from the flavor compositions over an extended period of time under hydrolytic conditions.
U.S. Pat. No. 4,253,473 describes smoking tobacco compositions or substitute smoking tobacco compositions which upon smoking release substantially evenly and uniformly over an extended period of time.
U.S. Pat. No. 3,818,107 describes a chewing gum containing a flavor release composition comprising polymer backbones with flavor groups appended thereto. The flavor moieties are released from the polymer backbone by hydrolysis which is achievable by mastication of chewing gums containing the flavor groups.
As an alternative method, the flavoring chemicals may be covalently bound to an auxilliary component to form a higher molecular weight molecule of low volatility. The flavorant is released upon pyrolysis, heating or solvolysis of the tobacco or food product.
In general, inventions employing the second strategy use an ester or carbonate linkage of a higher molecular weight molecule to an alcoholic flavor molecule. In such a system a flavor molecule is covalently bound to a polymer and may be depicted by the following generalized structure: ##STR2## wherein R.sub.1 represents a low alkyl group such as methyl, R.sub.2 represents a flavorant radical such as menthyl and n is an integer from 2 to 10,000. This approach has been demonstrated in a number of U.S. Patents. For example, U.S. Pat. No. 4,212,310 describes different flavored smoking tobacco products wherein some of the products contain an alcohol flavorant-release composition which delivers the flavor note of the alcohol upon pyrolysis.
U.S. Pat. No. 4,119,106 describes alcohol flavorant-release polymeric derivatives which are designed to enhance tobacco smoke by releasing an alcohol flavorant to tobacco smoke without wasting the natural flavor of the resultant main stream tobacco smoke.
U.S. Pat. Nos. 4,578,486 and 4,538,628 describe smoking tobacco compositions which contain dioxane diester flavorant-release additives. When subjected to normal smoking conditions such as cigarettes, the diester additive decomposes to release a volatile pyrolysis (alcohol or phenol) component which provides flavor-enhancing properties to the mainstream smoke and enhances the aroma of the sidestream smoke.
U.S. Pat. Nos. 4,701,282, 4,538,627 and 4,540,004 describe the use of ketoester or carbonate ester compounds as flavorant additives which under cigarette smoking conditions pyrolyze to release flavorants which enhance the flavor of the mainstream smoke and the aroma of sidestream smoke.
Acetals have also been used as vehicles to covalently bind aldehyde flavorants. For example, U.S. Pat. No. 4,296,137 describes the use of 1-ethoxy-1-ethanol acetate or a flavor or fragrance enhancer of a wide variety of consumable materials. The 1-ethoxy-1-ethanol acetate compound has the ability to liberate acetaldehyde in smoking tobacco. U.S. Pat. No. 4,280,011 describes the use of acetals as aldehyde generators in foodstuff applications. U.S. Pat. No. 3,625,709 describes food flavoring and aroma enhancers consisting of acetaldehyde combined with carbohydrates to form compositions which release acetaldehyde when combined with hot water or with cold water. U.S. Pat. No. 4,857,964 describes controlled release flavor compositions useful in flavor compositions which comprise flavor particles formed from a dispersion of flavor acetal or ketal in polymeric binders. The controlled release flavor compositions have multiple means of control, one of which is the hydrolysis of the flavor acetal or ketal. These controlled release flavor compositions are useful in chewing gums.
Finally, U.S. Pat. Nos. 4,690,157 and 4,607,118 describe tobacco compositions which contain flavor release additives which, under cigarette smoking conditions, pyrolyze in a "retro-aldol" fragmentation reaction into products which enhance the flavor and aroma of the cigarette smoke.
It is one object of the present invention to provide a series of novel compounds, as well as methods for their synthesis, useful as flavorants and as sustained release odorants to mask and/or to enhance the odors of burning tobacco products.
Another object of the present invention is to flavor cooked foods, e.g., microwaveable foods, which, during the cooking process, release flavorants into the food.
Yet another object of the present invention is to flavor chewing gum.